Vacuum breaker for internal combustion engines



Dec. 12, 1967 c MESERVE 3,357,414

v VACUUM BREAKER FOR INTERNAL COMBUSTION ENGINES Filed Feb. 15, 1965 3Sheets-Sheet 1 FIG. I

Movin Towards Idle Position INVENTOR.

Y r MW ZZZ? Dec. 12, 1967 F. c MESERVE 3,357,434

VACUUM BREAKER FOR INTERNAL COMBUSTION ENGI Filed Feb. 15, 1965 NBS 3Sheets-Sheet :3

FIG. 2

Deceleroting in Idle Position INVENTOR.

Dec. 12, 1967 F. C MESERVE.

VACUUM BREAKER FOR INTERNAL, COMBUSTION ENGINES Filed Feb. 15, 1965 SOL.RELAY 5 Sheets-Sheet .3

FIG. 3

United States Patent 3,357,414 VACUUM BREAKER FOR INTERNAL COMBUSTIONENGINES Forrest Clayton Meserve, 19 Peters St., North Andover, Mass.01845 Filed Feb. 15, 1965, Ser. No. 432,538 3 Claims. (Cl. 123-119)ABSTRACT OF THE DISCLOSURE A vacuum breaker for internal combustionengines comprising a casing having an air passage leading to the intakemanifold of the engine with valve seats of respectively large and smallareas and a single valve controlling the passage, the valve beingspring-biased toward said seats, and a throttle controlled air valve foradmitting atmospheric pressure to the area of said valve between theseats for unseating the valve in opposition to said spring.

This invention comprises a new and improved vacuum breaker for use withinternal combustion engines for the purpose of reducing the high vacuumin the cylinders and intake manifold when the carburetor valve is closedbut the engine is still turning over.

The action of such vacuum is objectionable because it causes oil to besucked past the piston rings where it will be burned in the cylinderswith the formation of carbon and also because it creates noxious exhaustfumes.

The device of my invention not only relieves the engine of this vacuumwhen it is not wanted but permits free influx of fresh air and soreduces overheating of the engine during deceleration.

To this end the vacuum breaker of my invention includes in its structurea casing having an air passage leading to the intake manifold of theengine with valve seats of respectively large and small area controllingthe passage. In the passage is a valve body having spaced shouldersfitting the respective valve seats, means for holding the valve inclosed position on both seats, and a valved air passage in the casingleading to the valve seat of larger area.

This deceleration valve automatically opens, venting the inlet manifoldto the atmosphere, when the butterfly valve closes and the vacuum ishigh, and closes when the vacuum becomes reduced to approximately twoinches or before the engine stalls.

Other deceleration valves have been produced but have not beensatisfactory because of popping in the carburetor, mufiler explosionsand stalling of the engine, due to an excessively lean fuel mixturecaused by the failure of the deceleration valve to close before thecarburetor butterfly valve is opened.

In the vacuum breaker of my invention I have eliminated the formation ofa lean mixture and resultant popping, stalling and muflier explosions byinstalling a damper between the valve and the carburetor-to-manifoldpassage. This damper is actuated by the carburetor linkage so that whenthe foot throttle is depressed the damper is closed just before thecarburetor butterfly opens, and is opened just after the butterfly valvecloses.

The valve of my improved breaker is of a diminishing resistance type,and spring actuated so that a vacuum higher than that created at idleengine speed is required to open it. It is held open by the flow of airuntil the flow is reduced nearly to that required for idle speed andthen automatically returns the manifold to pressure required for idling.

To insure that this valve does not open prematurely and that it does notflutter when closing, it has incorporated in its design two-stageatmospheric exposure. This design normally exposes only one-half thepiston area to the atmosphere, except at the exact time when the valveis to open. At this time a cam-operated valve admits atmosphericpressure to the entire surface of the piston. This provides twice thenormal load on the springs and as a result the piston is lifted off itsseat, opening the valve to its full extent instantly.

These and other features of the invention will be best understood andappreciated from the following description of a preferred embodimentthereof selected for purposes of illustration and shown in theaccompanying drawings in which FIGS. 1 and 2 are views in elevationpartly in section showing the valve in closed and open positions, and

FIGS. 3 and 4 are fragmentary views illustrating modified constructions.

In the drawings a carburetor of conventional type is shown as secured tothe intake manifold 10 of a gas engine through a T-fitting 11 and aflanged collar 12. The carburetor 13 has an overhead air inlet 14 andthe flow of its combustible gas mixture is controlled by a butterflyshoulder valve 15 mounted on a shaft 16 journaled in the collar 12.

The valve shaft 16 is connected to a rocker arm 17 having lost motionrelation with an upstanding arm 19 operated by a throttle rod 18. Thearm 17 is connected to a spring 20 tending at all times to maintain thebutterfly valve 15 in closed position.

The arm 19 is journaled on shaft 16 and a T-shaped sector head 21 with acurved surface from which projects a one-way tripping latch 22 arrangedto depress and open a ball valve 23 located in position to be contactedby the latch in the counter-clockwise movement of the head 21. When thehead 21 is moved in the opposite direction the latch 22 yields withoutaffecting the valve 23.

The ball valve 23 controls an air passage 24 formed in a tubular casing25 connected through a coupling 26 to the threaded transverse outlet 27of the T 11. At its outer end the casing 25 receives a threaded nipple28 forming an air inlet passage.

Within the casing 25 are formed two annular valve seats. The smaller isformed by an annular shoulder 29 and the larger by an annular shoulder30.

Within the casing 12 is mounted a cylindrical valve 31 carrying on itsouter end a washer 32 which cooperates with the valve seat 29 tocompletely close the air inlet passage when seated as shown in FIG. 1.The valve body is shouldered to fit within the valve seat 30 thusforming a second closure for the air passage 28. The air passage 24leads into the valve chamber in an area surrounding the valve 31 inposition to admit air at atmospheric pressure against an annular area ofthe shoulder of the valve 31.

The valve 31 is normally maintained in closed position by toggle springs33 supported at their outer ends by a shoulder in the coupling 26. Thesprings 33 are selected and arranged to balance the valve body 31 inclosed position against the normal vacuum created in the running engine.However, when the throttle valve 15 is closed, shutting off or reducingthe flow of combustible gas and so increasing the vacuum, the valve 23is opened by the reverse movement of the throttle rod and atmosphericpressure is admitted to the annular outer area of the valve body thusovercoming the resistance of the springs 33 and snapping the valve bodyinto full open position admitting full flow of fresh air through theinlet passage 28 to the manifold and subjecting the full circular areaof the valve 31 to atmospheric pressure.

The opening of the ball valve 23 causes the first stage atmosphericexposure of the cylindrical valve 31 under relatively low pressure butsufficient to overcome the toggle springs 33. The second stageatmospheric exposure of the valve 31 then takes place under augmentedpressure acting on the full circular area of the valve.

A damper valve 34 is mounted on a shaft 35 in the outlet 0f the T 11 andprovided with a counterweight head 36 which tends to hold the valvenormally in open position thus leaving the air passage 28 entirely undercontrol of the valve 31. However when the system requires fluidpressure, as for operating brakes, the valve 34 is moved to closedposition as indicated in FIG. 1 by cam action of the sector head 21 on ashort arm projecting from the shaft 35.

The valve 34 may, however, be controlled through a solenoid 50 assuggested in FIG. 4. The solenoid operates a rod 51 having an operatingconnection with the arm of the valve 34 and in circuit with a switch 52that may be located in convenient reach of the driver or included in thebacking light circuit.

An alternative construction for causing the valve 31 to open is shown inFIG. 3 where an elbow fitting 40 is substituted for the nipple 28 ofFIGS. 1 and 2. To this fitting is secured a solenoid 41 operating aplunger and rod 42 that is arranged to contact the .outer end of thevalve 31 and push it off its seats against the action of the springs33."1'he solenoid is in circuit with a switch 44- arranged to be closedby action of the latch 22 when the center head 21 is moved upwardlytoward driving position.

In normal operation at moderate speeds the manifold pressure may rise ashigh as 27 inches or more. In deceleration under these circumstancesthere is unbalance between the ratio of air and fuel drawn into themanifold. This causes a continual flow of unburned gas through theexhaust and continues until the engine reaches idling speed. When thethrottle is closed and the manifold pressure increased the two-stagevalve automatically opens thus reducing the manifold pressure to about 7inches. Then the air flow maintains the wide open valve position untilthe manifold pressure is reduced to about two inches at which time theair flow rate balances the requirement of the idling engine. When thiscondition is reached the valve automatically closes so that the manifoldmay return to its normal pressure.

Having thus disclosed my invention and described in detail a preferredembodiment thereof I claim as new and desire to secure by LettersPatent:

1. A vacuum breaker comprising a single tubular casing having an airpassage leading to the carburetor and the intake manifold of an internalcombustion engine, concentrically arranged and longitudinally spacedvalve seats associated with said passage, a valve body having concentricshoulders fitting the respective valve seats in said tubular casing,toggle springs holding the valve closed upon one of said valve seats, anormally closed air passage in said casing leading to the other of saidvalve seats, an air valve for admitting atmospheric pressure to thesecond of said valve seats, for unseating the valve body in oppositionto said toggle spring, and saidvacuum breaker being characterized inthat the air valve -is opened by a rocking cam having a 10st motionconnection with the carburetor valve of the engine.

2. A vacuum'breaker comprising a single tubular casing having an airpassage leading to the carburetor and the intake manifold of an internalcombustion engine, concentrically arranged and longitudinally spacedvalve seats associated with said passage, a valve body having concentricshoulders fitting the respective valve seats in said tubular casing,toggle springs holding the valve closed upon one of said valve seats, anormally closed air passage in said casing leading to the other of saidvalve seats, an air valve for admitting atmospheric pressure to thesecond of said valve seats, for unseatting the valve body in oppositionto said toggle spring, and said vacuum breaker being characterized inthat an additional butterfiy valve is provided in said air passage withconnections to said rocking cam for closing the passage to reestablishvacuum in the manifold.

3. A vacuum breaker as described in claim 1, further characterized inthat a damper valve is provided in said first mentioned air passage withmeans for closing said damper valve independently of the main valve.

References Cited UNITED STATES PATENTS MARK NEWMAN, Primary Examiner.

AL LAWRENCE SMITH, Examiner.

1. A VACUUM BREAKER COMPRISING A SINGLE TUBULAR CASING HAVING AN AIRPASSAGE LEADING TO THE CARBURETOR AND THE INTAKE MANIFOLD OF AN INTERNALCOMBUSTION ENGINE, CONCENTRICALLY ARRANGED AND LONGITUDINALLY SPACEDVALVE SEATS ASSOCIATED WITH SAID PASSAGE, A VALVE BODY HAVING CONCENTRICSHOULDERS FITTING THE RESPECTIVE VALVE SEATS IN SAID TUBULAR CASING,TOGGLE SPRINGS HOLDING THE VALVE CLOSED UPON ONE OF SAID VALVE SEATS, ANORMALLY CLOSED AIR PASSAGE IN SAID CASING LEADING TO THE OTHER OF SAIDVALVE SEATS,